will i run 2 lean?

iain_c · Feb 17, 2006

Another tech question poeple.
I have a cat back system and a viper on my cup.
Will it run lean on the rolling road day tomrrow? Im a bit worried!!

Thanks iain

OliS · Feb 17, 2006

Going by what I have heard about running a Viper of the R'sport Clio's then I think you may be running lean in the top of the rev range. When I have had cars on the rollers before, I have always got an air/fuel ratio reading, so hopefully Janspeed's rollers will do the same.

Nik · Feb 17, 2006

Yeah, i meant to ask Janspeed that actually, i would like to get an AFR reading too if possible.

Fred · Feb 17, 2006

yeah it'll be lean, but not dangerously

the F4R's like to run a tiny bit lean

iain_c · Feb 17, 2006

thanks fred...do you suggest a remap?

Fred · Feb 18, 2006

well let me put it this way

std 172 + viper + catback exhaust = 174bhp

as above + remap = 184bhp

done on Power Engineerings RR

iain_c · Feb 21, 2006

Fred...got 144.8 at the wheels on the janspeed rollers (180 bhp @ fly?)
With a viper& catback....i guess it depends on the rollers?

Fred · Feb 22, 2006

sounds fair enough, and yes rollers do vary massivley

pleased with the result?

iain_c · Feb 22, 2006

Yer sounded ok to me .... I was expecting about 160 bhp lol
Thanks for the info Fred.

AndyC · Feb 25, 2006

filter and exhaust dont really make a huge difference to AFR readings....

if you get manifold matching done then it does run a little lean...14's in part throttle load areas where as for power you want to see 12.9

however many have run this spec with no remap and found it ok....

BUT

when they have had a remap they have noticed good gains in power and drivability.